<template>
    <div>
        <router-link tag="div" class="header-abs" to="/" v-show="showAbs">
            <div class="iconfont header-abs-back">&#xe624;</div>
        </router-link>
        <div class="header-fixed"
            v-show="!showAbs"
            :style="opacityStyle"
        >
            景点详情
            <router-link to='/'>
                <div class="iconfont header-fixed-back">&#xe624;</div>
            </router-link>
        </div>
    </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = {
          opacity
        }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
@import '~styles/varibles.styl';
.header-abs
    position absolute
    left .2rem
    top .2rem
    height .8rem
    width .8rem
    line-height .8rem
    border-radius .4rem
    text-align center
    background rgba(0,0,0,.8)
    .header-abs-back
        color #ffffff
        font-size .4rem
.header-fixed
    z-index 2
    position fixed
    top 0
    left 0
    right 0
    height .86rem
    line-height .86rem
    text-align center
    color #ffffff
    background $bgColor
    font-size .4rem
    .header-fixed-back
        position absolute
        top 0
        left 0
        width .64rem
        text-align center
        font-size .4rem
        color #ffffff
</style>
